Integrated circuits including ild structure, systems, and fabrication methods thereof

ABSTRACT

An integrated circuit includes a gate of a transistor disposed over a substrate. A connecting line is disposed over the substrate. The connecting line is coupled with an active area of the transistor. A level difference between a top surface of the connecting line and a top surface of the gate is about 400 Å or less. A via structure is coupled with the gate and the connecting line. A metallic line structure is coupled with the via structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority of U.S. Provisional PatentApplication Ser. No. 61/176,002, filed on May 6, 2009, which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to the field of semiconductordevices, and more particularly, to integrated circuits includinginterlayer dielectric (ILD) structure, systems, and fabrication methodsthereof.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced rapidgrowth. Technological advances in IC materials and design have producedgenerations of ICs where each generation has smaller and more complexcircuits than the previous generation. However, these advances haveincreased the complexity of processing and manufacturing ICs and, forthese advances to be realized, similar developments in IC processing andmanufacturing are needed.

In the course of IC evolution, functional density (i.e., the number ofinterconnected devices per chip area) has generally increased whilegeometry size (i.e., the smallest component (or line) that can becreated using a fabrication process) has decreased. This scaling downprocess generally provides benefits by increasing production efficiencyand lowering associated costs. Such scaling-down also produces arelatively high power dissipation value, which may be addressed by usinglow power dissipation devices such as complementarymetal-oxide-semiconductor (CMOS) devices.

As mentioned above, the trend in the semiconductor industry is towardsthe miniaturization or scaling of integrated circuits, in order toprovide smaller ICs and improve performance, such as increased speed anddecreased power consumption. While aluminum and aluminum alloys weremost frequently used in the past for the material of conductive lines inintegrated circuits, the current trend is to use copper for a conductivematerial because copper has better electrical characteristics thanaluminum, such as decreased resistance, higher conductivity, and ahigher melting point.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is best understood from the following detaileddescription when read with the accompanying figures. It is emphasizedthat, in accordance with the standard practice in the industry, variousfeatures are not drawn to scale and are used for illustration purposesonly. In fact, the dimensions of the various features may be arbitrarilyincreased or reduced for clarity of discussion.

FIG. 1 is a schematic cross-sectional view illustrating an exemplaryintegrated circuit including a transistor coupled with a metallic linestructure.

FIG. 2 is a schematic cross-sectional view illustrating anotherintegrated circuit including a butting contact.

FIG. 3 is a flowchart illustrating an exemplary method for forming anexemplary integrated circuit including a transistor coupled with ametallic line structure.

FIG. 4 is a schematic drawing illustrating a system including anexemplary integrated circuit disposed over a substrate board.

DETAILED DESCRIPTION

The CMOS transistor includes a conventional low dielectric constant(low-k) interlayer dielectric (ILD) structure. The conventional ILDstructure uses an ILD material around a transistor formed on asubstrate. The ILD material can be formed by a high aspect ratio process(HARP). A contact is formed on a gate of the transistor and anothercontact is formed on an active area of the substrate. Another ILDmaterial formed by a high density plasma chemical vapor deposition (HDPCVD) can be around the contacts. Metal lines are formed on the contactsfor an electrical connection.

It is found that a top surface of the gate and a top surface of thesubstrate have a step height. The step height results in a leveldifference between the contact disposed on the gate of the transistorand the contact disposed on the active area of the substrate. Due to thelevel difference, it is difficult to form contact openings toaccommodate the contacts that have different depths. For example, if asingle etch process is provided to form the contact openings, either theetch process may damage the gate of the transistor or the etch processmay not etch a desired thickness of the ILD layers, failing to exposethe active area of the substrate.

To solve the issue described above, a double patterning process has beenproposed. The double patterning process uses two photoresist masks, twophotolithographic processes, and two etch processes to separately definethe contact opening for the contact disposed on the gate of thetransistor and the contact opening for the contact disposed on theactive area of the substrate. The double patterning process increasesthe cost of manufacturing the integrated circuits and/or makes themanufacturing process complicated.

It is found that the conventional ILD structure uses tungsten (W) plugsdisposed within the contact openings for the electrical connection. Ifthe integrated technique shrinks to 22 nm or less, it is found that theresistance of the W plugs jumps up to an undesired level.

It is also found that the conventional ILD structure uses ILD materialsformed by a HARP and HDP CVD. The ILD materials have dielectricconstants higher than low-k dielectric materials or extreme low-kdielectric materials. Due to the high dielectric constants of the ILDmaterials, the RC-time delay of the conventional ILD structure is notdesired.

From the foregoing, integrated circuits having a low-k ILD structure,systems, and method for forming the integrated circuits are desired.

It is understood that the following disclosure provides many differentembodiments, or examples, for implementing different features of theinvention. Specific examples of components and arrangements aredescribed below to simplify the present disclosure. These are, ofcourse, merely examples and are not intended to be limiting. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.Moreover, the formation of a feature on, connected to, and/or coupled toanother feature in the present disclosure that follows may includeembodiments in which the features are formed in direct contact, and mayalso include embodiments in which additional features may be formedinterposing the features, such that the features may not be in directcontact. In addition, spatially relative terms, for example, “lower,”“upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,”“top,” “bottom,” etc. as well as derivatives thereof (e.g.,“horizontally,” “downwardly,” “upwardly,” etc.) are used for ease of thepresent disclosure of one features relationship to another feature. Thespatially relative terms are intended to cover different orientations ofthe device including the features.

FIG. 1 is a schematic cross-sectional view illustrating an exemplaryintegrated circuit including a transistor coupled with a metallic linestructure. In FIG. 1, a transistor 110 can be formed over a substrate101. The transistor 110 can include a gate 111 and source/drain regions(not shown) adjacent to the gate 111. A connecting line 120 can bedisposed over the substrate 101. The connecting line 120 can be coupledwith an active area of the transistor 110. A via structure 135 includingvias 135 a and 135 b can be coupled with the gate 111 and the connectingline 120, respectively. A metallic line structure 140 including metalliclines 140 a and 140 b can be coupled with the via structure 135.

In some embodiments, the substrate 101 can include an elementarysemiconductor including silicon or germanium in crystal,polycrystalline, or an amorphous structure; a compound semiconductorincluding silicon carbide, gallium arsenic, gallium phosphide, indiumphosphide, indium arsenide, and indium antimonide; an alloysemiconductor including SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, andGaInAsP; any other suitable material; or combinations thereof. In oneembodiment, the alloy semiconductor substrate may have a gradient SiGefeature in which the Si and Ge composition change from one ratio at onelocation to another ratio at another location of the gradient SiGefeature. In another embodiment, the alloy SiGe is formed over a siliconsubstrate. In another embodiment, a SiGe substrate is strained.Furthermore, the semiconductor substrate may be a semiconductor oninsulator, such as a silicon on insulator (SOI), or a thin filmtransistor (TFT). In some examples, the semiconductor substrate mayinclude a doped epi layer or a buried layer. In other examples, thecompound semiconductor substrate may have a multilayer structure, or thesubstrate may include a multilayer compound semiconductor structure.

The transistor 110 can include at least one gate dielectric layer (notshown). The gate dielectric layer can be a single layer or a multi-layerstructure. In some embodiments, the at least one gate dielectric layercan include an interfacial layer, e.g., a silicon oxide layer, and ahigh-k dielectric layer over the silicon oxide layer. In embodimentsusing a high-k dielectric layer, the high-k dielectric layer may includehafnium oxide (HfO₂), hafnium silicon oxide (HfSiO), hafnium siliconoxynitride (HfSiON), hafnium tantalum oxide (HfTaO), hafnium titaniumoxide (HfTiO), hafnium zirconium oxide (HfZrO), other suitable high-kdielectric materials, and/or combinations thereof. The high-k materialmay further be selected from metal oxides, metal nitrides, metalsilicates, transition metal-oxides, transition metal-nitrides,transition metal-silicates, oxynitrides of metals, metal aluminates,zirconium silicate, zirconium aluminate, silicon oxide, silicon nitride,silicon oxynitride, zirconium oxide, titanium oxide, aluminum oxide,hafnium dioxide-alumina (HfO₂—Al₂O₃) alloy, other suitable materials,and/or combinations thereof. The high-k dielectric layer may be formedby any suitable process, such as atomic layer deposition (ALD), chemicalvapor deposition (CVD), physical vapor deposition (PVD), remote plasmaCVD (RPCVD), plasma enhanced CVD (PECVD), metal organic CVD (MOCVD),sputtering, plating, other suitable processes, and/or combinationsthereof.

Referring to FIG. 1, the gate 111 can be disposed over the substrate101. The gate 111 can include at least one semiconductor or conductivematerial, such as silicon, polysilicon, amorphous silicon,silicon-germanium, metallic material, and/or any combinations thereof.In embodiments using metallic material, the gate 111 can includematerials such as metal, metal carbide, metal nitride, or othermaterials that can provide desired work function for transistors. Inembodiments forming an NMOS transistor, the gate 111 can be an n-typemetal gate that is capable of providing a work function value of about4.5 eV or less for the NMOS transistor. In other embodiments forming aPMOS transistor, the gate 111 can be a p-type metal gate layer that iscapable of providing a work function value of about 4.8 eV or more forthe PMOS transistor. The gate 111 can be formed by any suitable process.For example, the gate 111 may be formed by deposition, photolithographypatterning, and etching processes, and/or combinations thereof. Thedeposition processes may include PVD, CVD, ALD, sputtering, plating,other suitable methods, and/or combinations thereof. Thephotolithography patterning processes may include photoresist coating(e.g., spin-on coating), soft baking, mask aligning, exposure,post-exposure baking, developing the photoresist, rinsing, drying (e.g.,hard baking), other suitable processes, and/or combinations thereof. Thephotolithography exposing process may also be implemented or replaced byother proper methods such as maskless photolithography, electron-beamwriting, ion-beam writing, and molecular imprint. The etching processesmay include dry etching, wet etching, and/or other etching methods(e.g., reactive ion etching). The etching process may also be eitherpurely chemical (plasma etching), purely physical (ion milling), and/orcombinations thereof.

The source/drain regions (not shown) of the transistor 110 can be n-typedoped regions having dopants such as Arsenic (As), Phosphorus (P), othergroup V element, or the combinations thereof or p-type doped regionshaving dopant such as Boron (B) or other group III element. In someembodiments, the source/drain regions can include silicide for lowresistances. The silicide may comprise materials such as nickel silicide(NiSi), nickel-platinum silicide (NiPtSi), nickel-platinum-germaniumsilicide (NiPtGeSi), nickel-germanium silicide (NiGeSi), ytterbiumsilicide (YbSi), platinum silicide (PtSi), iridium silicide (IrSi),erbium silicide (ErSi), cobalt silicide (CoSi), other suitablematerials, and/or combinations thereof. The materials utilized to createthe silicide may be deposited using PVD such as sputtering andevaporation; plating; CVD such as plasma enhanced CVD (PECVD),atmospheric pressure CVD (APCVD), low pressure CVD (LPCVD), high densityplasma CVD (HDPCVD) and atomic layer CVD (ALCVD); other suitabledeposition processes; and/or combinations thereof. After deposition, thesalicidation process may continue with a reaction between the depositedmaterial and the doped regions at an elevated temperature that isselected based on the specific material or materials. This is alsoreferred to as annealing, which may include a Rapid Thermal Processing(RTP). The reacted silicide may require a one step RTP or multiple stepRTPs.

In some embodiments, spacers (not shown) can be formed on sidewalls ofthe gate 111. The spacers can include materials such as oxide, nitride,oxynitride, other dielectric materials, and/or combinations thereof. Theformation of the spacers can include forming a dielectric layer over thegate 111 and then etching the dielectric layer to form the spacers.

Referring to FIG. 1, the connecting line 120 can be disposed over thesubstrate 101. The connecting line 120 can be electrically coupled withthe active area (not shown) of the transistor 110. The active area caninclude a region of the transistor 110 that is capable of providing achannel between the source and the drain of the transistor 110. Inembodiments using a planar metal-gate-oxide (MOS) transistor, the activearea of the transistor 110 can be disposed within the substrate 101. Inother embodiments using a FIN field effect transistor (FIN FET), theactive area of the transistor 110 can be disposed in a FIN of thetransistor 110. The connecting line 120 can include materials such astungsten, aluminum, copper, titanium, tantulum, titanium nitride,tantalum nitride, nickel silicide, cobalt silicide, other properconductive materials, and/or combinations thereof. The connecting line120 can be formed by any suitable processes, such as deposition,photolithography, and etching processes, and/or combinations thereof. Inembodiments, the process for forming the connecting line 120 can bereferred to as a M0_OD process. The layer of the connecting line 120 canbe referred to as a M0-OD layer. In embodiments using a 22-nm technique,a level difference between a top surface 111 a of the gate 111 and a topsurface 120 a of the connecting line 120 can be about 400 Å or less. Inother embodiments, the top surface 111 a of the gate 111 can besubstantially level with the top surface 120 a of the connecting line120. It is noted that the 400-Å level difference is merely exemplary.One of skill in the art is capable of modifying the level difference toachieve a desired ILD structure.

Referring again to FIG. 1, at least one dielectric layer 105 can bedisposed over the substrate 101 and around the gate 111 and theconnecting line 120. The dielectric layer 120 may include materials suchas oxide, nitride, oxynitride, low-k dielectric material, ultra low-kdielectric material, or any combinations thereof. The dielectric layer105 may be formed by, for example, a CVD process, a HDP CVD process, aHARP, a spin-coating process, other deposition process, and/or anycombinations thereof. In embodiments, the dielectric layer 105 can bereferred to as an interlayer dielectric (ILD). In other embodiments,additional dielectric layer (not shown) can be formed below or over thedielectric layer 105 and around the gate 111 and the connecting line120.

In FIG. 1, an etch stop layer (ESL) 125 can be formed over thedielectric layer 105. The ESL 125 can include materials such as siliconnitride, silicon-carbon based materials such as silicon carbide (SiC) orcarbon-doped silicon oxide, carbon-doped oxide, or combinations thereof.The ESL 125 can be formed by plasma enhanced chemical vapor deposition(PECVD), CVD process such as high-density plasma CVD (HDPCVD), atomiclayer CVD (ALCVD), or the like.

Referring again to FIG. 1, at least one dielectric layer 130 can bedisposed over the ESL 125. The dielectric layer 130 may includematerials such as low-k dielectric material, ultra low-k dielectricmaterial, extreme low-k material, or any combinations thereof. Thedielectric layer 130 may be formed by, for example, a CVD process or aspin-coating process. In some embodiments, additional dielectric layer(not shown) can be formed below or over the dielectric layer 130 andaround the via structure 135 and/or the metallic line structure 140.

As noted, the via structure 135 can include a plurality of vias, e.g.,vias 135 a and 135 b. The vias 135 a and 135 b can be coupled with thegate 111 and the connecting line 120, respectively. The metallic linestructure 140 can include a plurality of metallic lines, e.g., metalliclines 140 a and 140 b. The metallic lines 140 a and 140 b can be coupledwith the vias 135 a and 135 b, respectively. In some embodiments, thevia structure 135 can be referred to as a single damascene structure. Inother embodiments, the via structure 135 and the metallic line structure140 can be referred to as a dual damascene structure.

The dual damascene structure can be formed by, for example, formingopenings (not shown) by means which involves coating and patterning aphotoresist layer (not shown) on the dielectric layer 130 and plasmaetch transferring the opening through the dielectric layer 130. Theremaining photoresist layer can be stripped by an ashing and/or with anapplication of a liquid stripper. In some embodiments, a diffusionbarrier layer (not shown) including materials such as Ta, TaN, Ti, TiN,TaSiN, W, WN, other barrier layer material, and/or combinations thereofcan be formed on the sidewalls of the openings by, for example, a CVDprocess, a PECVD process, or an atomic layer deposition (ALD). Thediffusion barrier layer can be formed on the sidewalls and/or bottom ofthe opening. A following metallic layer including materials such ascopper, tungsten, Al, Al/Cu, other conductive material, and/orcombinations thereof can be deposited by a CVD, PVD, ALD, electroplatingmethod, and/or other process to fill the openings to form the dualdamascene structure. The damascene structure can be achieved by achemical mechanical polish (CMP) process that can polish the metalliclayer, forming the metallic lines 140 a and 140 b.

It is noted that more ESLs, dielectric layers, via structures, metallicline structures, and/or other semiconductor structure can be formed overthe metallic line structure 140 and the dielectric layer 130 to achievea desired interconnect structure. One of skill in the art can modifyprocesses, materials, and/or mask layers to achieve a desired integratedcircuit.

FIG. 2 is a schematic cross-sectional view illustrating anotherintegrated circuit including a butting contact. Items of FIG. 2 that arethe same items in FIG. 1 are indicated by the same reference numerals,increased by 100. In FIG. 2, the integrated circuit 200 can include thevia structure 235 electrically coupling the gate 211 and the connectingline 220. The gate 211 can be adjacent to the connecting line 220. Avoltage provided through the via structure 235 can be applied to thegate 211 and the connecting line 220. In some embodiments, a dielectriclayer, a barrier layer, and/or other material (not shown) can bedisposed between the gate 211 and the connecting line 220.

In some embodiments, the via structure 235 can be referred to as abutting contact. In embodiments using a 22-nm technique, a step heightbetween a top surface 211 a of the gate 211 and a top surface 220 a ofthe connecting line 220 can be about 400 Å or less. In otherembodiments, the top surface 211 a of the gate 211 can be substantiallylevel with the top surface 220 a of the connecting line 220.

FIG. 3 is a flowchart illustrating an exemplary method for forming anexemplary integrated circuit including a transistor coupled with ametallic line structure. Referring to FIGS. 1 and 3, a process 300 forforming a metallic line structure, e.g., the metallic line structure140, coupled with a gate of a transistor, e.g., the gate 111, and aconnecting line, e.g., the connecting line 120, can include followingsteps.

In Step 310, the gate 111 of the transistor 110 can be formed over thesubstrate 101. In Step 320, the connecting line 120 can be formed overthe substrate 101. The connecting line 120 can be coupled with an activearea of the transistor 110. In embodiments using a 22-nm technique, alevel difference between the top surface 111 a of the gate 111 and thetop surface 120 a of the connecting line 120 can be about 400 Å or less.In other embodiments, the top surface 111 a of the gate 111 can besubstantially level with the top surface 120 a of the connecting line120. In Step 330, the via structure 135 and the metallic line structure140 coupled with the gate 111 and the connecting line 120 can be formed.It is noted that the method 300 described above in conjunction with FIG.3 can be used to form the integrated circuit 200 shown in FIG. 2.

As noted, the conventional ILD structure uses a double-patterningprocess to define contact openings exposing the top surface of the gateof the transistor and the top surface of the active area of thesubstrate. The double-patterning process includes two masks, twophotolithographic processes, and two etch processes to separately definethe contact opening for the W-plug contact disposed on the gate and thecontact opening for the W-plug contact disposed on the active area ofthe substrate.

In contrary to the conventional ILD process, the method 300 describedabove in conjunction with FIG. 3 forms the gate 111 and the connectingline 120 over the substrate 101. As noted, the top surface 111 a of thegate 111 can be substantially level with the top surface 120 a of theconnecting line 120. A single via mask, a single photolithographicprocess, and a single etch process can simultaneously define via holesfor the vias 135 a and 135 b. While defining the via opening for the via135 b, the method 300 can define the via opening for the via 135 a,substantially free from damaging the gate 111.

As noted, the conventional ILD structure has the W-plug contact disposedbetween the gate of the transistor and the metal line. Different fromthe conventional ILD structure, the integrated circuit 100 include thevia 135 a coupled between the gate 111 and the metallic line 140 a. Thevia 135 a can be a single or a portion of a dual damascene structurethat uses a conductive material such as copper. The copper via 135 a candesirably reduce the resistance between the gate 111 and the metallicline 140 a.

It is noted that the conventional ILD structure includes ILD materialsformed by HDP CVD or HARP disposed around the W-plug contacts. Differentfrom the conventional ILD structure, the integrated circuit 100 caninclude the dielectric material 140 such as ultra low-k material orextreme low-k material disposed around the vias 135 a and 135 b. A RCtime delay resulting from the vias 135 a and 135 b and the dielectricmaterial 140 can be desirably reduced.

It is also found that the integrated circuit 100 uses the connectingline 120 instead of a W-plug contact of the conventional ILD structure.The connecting line 120 can provide a desired resistance for electricalconnection between the active area of the transistor 110 and the via 135b.

FIG. 4 is a schematic drawing illustrating a system including anexemplary integrated circuit disposed over a substrate board. In FIG. 4,a system 400 can include an integrated circuit 402 disposed oversubstrate board 401. The substrate board 401 can include a printedcircuit board (PCB), a printed wiring board and/or other carrier that iscapable of carrying an integrated circuit. The integrated circuit 402can be similar to the integrated circuit 100 or 200 described above inconjunction with FIGS. 1 and 2, respectively. The integrated circuit 402can be electrically coupled with the substrate board 401. In someembodiments, the integrated circuit 402 can be electrically coupled withthe substrate board 401 through bumps 405. In other embodiments, theintegrated circuit 402 can be electrically coupled with the substrateboard 401 through wire bonding. The system 400 can be part of anelectronic system such as computers, wireless communication devices,computer-related peripherals, entertainment devices, or the like.

In some embodiments, the system 400 including the integrated circuit 402can provides an entire system in one IC, so-called system on a chip(SOC) or system on integrated circuit (SOIC) devices. These SOC devicesmay provide, for example, all of the circuitry needed to implement acell phone, personal data assistant (PDA), digital VCR, digitalcamcorder, digital camera, MP3 player, or the like in a singleintegrated circuit.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

1. An integrated circuit comprising: a gate of a transistor disposedover a substrate; a connecting line disposed over the substrate, theconnecting line being coupled with an active area of the transistor, alevel difference between a top surface of the connecting line and a topsurface of the gate being about 400 Å or less; a via structure beingcoupled with the gate and the connecting line; and a metallic linestructure being coupled with the via structure.
 2. The integratedcircuit of claim 1, wherein the top surface of the connecting line issubstantially level with the top surface of the gate.
 3. The integratedcircuit of claim 1, wherein the gate is adjacent to the connecting line.4. The integrated circuit of claim 1, wherein the via structure and themetallic line structure constitute a dual damascene structure.
 5. Theintegrated circuit of claim 1, wherein the gate is a metallic gate andthe connecting line is a tungsten-containing line.
 6. The integratedcircuit of claim 1, wherein the via structure comprising a copper viadisposed between the gate and the metallic line structure.
 7. A systemcomprising: a board substrate; and an integrated circuit electricallycoupled with the printed circuit board, the integrated circuitcomprising: a gate of a transistor disposed over a substrate; aconnecting line disposed over the substrate, the connecting line beingcoupled with an active area of the transistor, a level differencebetween a top surface of the connecting line and a top surface of thegate being about 400 Å or less; a via structure being coupled with thegate and the metallic line; and a metallic line structure being coupledwith the via structure.
 8. The system of claim 7, wherein the topsurface of the connecting line is substantially level with the topsurface of the gate.
 9. The system of claim 7, wherein the gate isadjacent to the connecting line.
 10. The system of claim 7, wherein thevia structure and the metallic line structure constitute a dualdamascene structure.
 11. The system of claim 7, wherein the gate is ametallic gate and the connecting line is a tungsten-containing line. 12.The system of claim 7, wherein the via structure comprising a copper viadisposed between the gate and the metallic line structure.
 13. A methodfor forming an integrated circuit, the method comprising: forming a gateof a transistor over a substrate; forming a connecting line over thesubstrate, the connecting line being coupled with an active area of thetransistor, a level difference between a top surface of the connectingline and a top surface of the gate being about 400 Å or less; andforming a via structure and a metallic line structure being coupled withthe gate and the connecting line.
 14. The method of claim 13, whereinthe top surface of the connecting line is substantially level with thetop surface of the gate.
 15. The method of claim 13, wherein forming thevia structure and the metallic line structure comprises performing adual damascene process.
 16. The method of claim 13, wherein the gate isadjacent to the connecting line.
 17. The method of claim 13, whereinforming the gate of the transistor over the substrate comprises forminga metallic gate of the transistor over the substrate.
 18. The method ofclaim 13, wherein forming a connecting line over the substrate comprisesforming a tungsten-containing line over the substrate.